When I first brought my daughter, Genie, home from the hospital, I expected a mixed reaction from her big sister, Clara, then 3. It was mixed, all right, a bubbling brew of jealousy and curiosity—but mainly, she was curious about how I'd react if she either poked Genie or hugged her too hard. Concerned, I did what I could to help Clara adjust. We spent quality time alone. I read her those “I'm a Big Sister” books. Finally, one morning she was nothing but nice to Genie. “Good girl!” I gushed (you don't work at Parenting without learning about positive reinforcement). Then I gave her a red lollipop. (Yeah, you also don't work here without learning not to use a treat as a reward, but I was on maternity leave, k?)

I left the room for two minutes, then returned to nurse Genie. As I bent over her bassinet, I stopped in my tracks: She was smeared head to toe with red-lollipop juice.

Welcome to the wonderful world of sibling relationships. That “smear campaign” was just the start of what I've witnessed (and refereed) as my kids have grown—everything from sandbox one-upmanship (who can build a bigger castle?) to tugs-of-war over the Wiimote. Which is not to say my kids aren't attached to each other—when one gets invited on a playdate, the other mopes at home till she returns. So why all the agita?

“The rivalry you see—whether your children are fighting for a toy or the first turn on a swing—is really rooted in a struggle for your love and attention,” says Frances Walfish, Psy.D., a child and family psychotherapist in Beverly Hills, CA, and author of The Self-Aware Parent. “Kids want to know that Mom's and Dad's eyes are on them and them alone.” Which can't happen unless you give away all your little guys except one (admittedly, it can be an appealing thought at certain times). Instead, try these friction-defusing strategies.

Toy Story

“Now that Dael is eight months old, he's moving around and playing more, and it's been hard for our daughter, Charlee, who's three, to share toys with him. When she sees Dael holding something she wants to play with, she snatches it out of his hand and cries.” —Mike Granek, Vancouver, British Columbia

What's Really Up? Charlee's protests are a way to get the spotlight, says Geoffrey E. Putt, Psy.D., director of parenting and family support services at Akron Children's Hospital, in Ohio. “In effect, she's saying, ‘Look, I used to be your only focus, but now what, my brother gets my toys, too?’ Even if all you do is scold her for not sharing, it's still attention, and any attention from a parent still feels good to a child,” he observes.

How to Stop the Squabbling: This might sound like the opposite of what you should do, but start by making sure each kid has a few toys that belong only to him or her. That's right, not all toys should be shared. (They don't call it Our Pretty Pony, now, do they?) “It's important for kids to know they have territory they can call their own,” explains Walfish. Be clear that all other toys are communal property. If the older sib snatches a plaything, that child loses it for a short time—the younger one can still play with it. Then encourage sharing, along with the rule that both need to behave in order to have access to the toy. Give them tons of positive feedback when they share, says Putt. Also give your older child a job: “Tell her ‘You're such a big kid, I need you to help your little brother learn how to play with toys properly,’ then suggest she show him how to use something, like a truck,” says Putt. “It'll help her feel valued and empowered, and almost superior—too much so to fight over every little toy. Then there's no longer a need for her to act up to get attention.”

Variable Interest Rates

“My girls are less than eighteen months apart—Annabelle Reese is three and Claire Elisabeth just turned two. But their personalities are totally different. My little one is a tomboy and loves playing outside, or with stuff like Tinkertoys. Her big sister likes to stay indoors and is sensitive to textures, so she likes to look at books or paint. They always want to be doing different activities.” —Amanda Griffith, Norton, MA

What's Really Up?Nothing but human nature, says Walfish: “It's very common for siblings, even ones who are the same sex or close in age, to have few shared interests,” she explains. Of course, fights over which activity you'll all do can turn into a major struggle, which is why it's important to make sure each child's interests and preferences are honored part of the time.

How to Stop the Squabbling: You can't always foist an unwanted activity on a small child simply because her sib loves it. But as a parent, you'll have to indulge each kid once in a while. If your younger child loves swimming and the other can't stand water, for instance, try to arrange a weekend morning alone with your little mermaid at the public pool. When choosing joint activities, “look for ones that offer a little something for each child, such as baking. The more hands-on child can help mix dough, while your other can use cookie cutters or help watch the timer,” Walfish suggests. Walks are another great idea. “They give a more active sibling a chance to do something a bit physical, while the other child can count squirrels or pick flowers,” she says.

Tough Breaks

“Gabriel, who's two, sometimes messes up his four-year-old brother's stuff—he'll knock down a Lego tower Michael's made or color on something he's drawn. Michael gets so frustrated that he'll sometimes crumple to the floor in a tantrum.” —John Bambenek, Champaign, IL

What's Really Up? At age 2, Gabriel isn't truly aware that what he's doing is wrong, Walfish says—and even if he has some inkling that his brother's colorful Lego tower maybe shouldn't be touched, he lacks the impulse control to keep his cute little mitts off it. Ditto for his drawing on Michael's artwork; he's just trying to get in on the fun by adding his own special touches (you know, like he did to your living room wall). But misguided imitation can lead to aggravation for everyone in the house.

How to Stop the Squabbling: An older kid is justified in feeling frustrated when a little sib screws up his stuff. “He's worked hard on his projects!” says Walfish. So first, offer sympathy: “Tell him ‘Your brother wasn't trying to be mean, he's just a baby, but what he did made you very angry,’” Walfish recommends. Don't try to talk him out of crying or throwing a fit, she adds. “Let him take it out on you, verbally, instead of taking it out on the younger child. He can tell his brother ‘Stop, I don't like that,’ but he needs to express his anger, so have him direct his remarks to you instead of traumatizing his baby brother by scolding him for things he doesn't understand.” After that, assure him that from now on, you'll find a safe place to put his finger paintings and other treasures. Towers can't be protected forever, but small ones can be placed on a shelf long enough for Dad or Grandma to admire later that day or week.

Party Poopers

“My daughters, Clara, five, and Lucie, three, love each other but get jealous of each other, too. On Lucie's last birthday, Clara threw tantrums because there weren't any presents for her. Next week Lucie's staying home with a sitter while my husband and I see Clara in a play, and Clara's been telling us to hire a boring babysitter so Lucie won't have fun without her.” —Jessica Rosenberg, Santa Clara, CA

What's Really Up? Clara's really making a grab for attention, says Putt: “To throw a tantrum during a party or try to insert her opinion into the discussion of what babysitter to hire is a way of protesting ‘What am I, chopped liver?’” he contends. The babysitter pushiness may be the more baffling of the two incidents; after all, everyone's gearing up to see Clara in a play. But all she hears are her parents talking about who will watch Lucie, so she isn't feeling yet that it's really “her” evening.

How to Stop the Squabbling: Sure, you might gain some peace in the short term by giving a consolation gift to a pouty kid on her sib's birthday or letting your kids select blah babysitters for one another. “But you have to teach them that everything can't always be equal,” says Putt. His advice: “The moment you negotiate with your child, you've lost. If one child is having a tantrum during the other's party, have an adult take her to another room to cool off—what makes her behavior powerful is that everyone is watching. Calmly tell her she can rejoin you when she's ready to have some fun.” When she returns (and she may not be ready after the first time), try giving her a party-helper job so she feels like a big kid and also saves face. As for self-serving babysitter suggestions, pull the plug on the conversation swiftly by saying sitters are strictly Mom's and Dad's concern. In cases like these, remind your child that even though her sib may be getting the lion's share of the attention this time, she's had plenty of special times, too. Tough love, baby. This is one of the times it's worth it.

Smack Attach

“Roxy's almost five, and she gives her fifteen-month-old brother, Simon, hugs and kisses, but when I'm the one who's giving him attention, she often feels a need to swoop in. She says to me, ‘Please don't do that, it's making me jealous,’ and then she pushes Simon with her foot, hits him, or puts her hand on his head. Luckily, she hasn't really hurt him, but sometimes he gets upset. I do, too.” —Rebecca Shapiro, New York City

What's Really Up? On the bright side, there's no guesswork involved in this scenario, is there? Roxy has said it herself: She's going all Jackie Chan on her bro because she's jealous. And really, it isn't hard to see why. It wasn't that long ago that Simon was still a baby, not old enough to actually be standing between her and Mom and receiving those big-kid hugs and kisses.

How to Stop the Squabbling: Your approach, says Walfish, has to be carefully balanced: “Give lots of love and attention to your older child every day, to help make her more secure, while at the same time having absolutely zero tolerance for any aggression. Tell her ‘You are not allowed to pinch or hurt smaller kids or anyone, ever.’ If it happens, give a time-out, and make sure she understands why.” That's not the same as telling her to stop acting jealous—in fact, Walfish says it's smart to let kids express their frustration. “Get a big piece of paper and markers, and encourage your child to draw a picture of how she feels or even just make big scribbles as she says ‘I don't like my baby brother today!’” Everyone needs to vent, and since your child is too young to ring up a pal for a download session at Starbucks, you're it. Shapiro finds that one cure is to spread the love: “I'll say to Roxy, ‘I think you just need a hug and a kiss.’ Then I'll give them to her and she'll often calm down.”

Feeding Frenzy

“Jonah's three, and he's mostly been pretty understanding since his little sister, Hannah, was born eight weeks ago—except when I'm breastfeeding her. I'll be nursing Hannah, and he'll climb up onto the couch, say he wants to play a game of catch with me, and then throw tennis balls at me!” —Kathy Dalton, Salt Lake City

What's Really Up? “No matter how hard a child tries to be tolerant, it's bound to be traumatic when a new baby arrives,” says Walfish. “There's always some underlying grief: ‘Why'd you have another child? Wasn't I enough?’” During times when your attention is mostly focused on the baby (as it naturally is during nursing), your older child's jealousy is particularly likely to get the better of him. Plus, “kids are like sharks. They sense when their parents are tied up—for example, when Mom's nursing—and act up during those times,” observes Putt. “Jonah's thinking, ‘I don't have many opportunities to do whatever I want. But I can see Mom's vulnerable right now, so let's find out if I can get some leverage!’” Hey, you can't blame a kid for trying.

How to Stop the Squabbling: Plan ahead, advises Putt. “Set aside a couple of toys your older child especially loves to play with, and put them out only when you're nursing. Explain that he can use them only while you're feeding the baby, and if he remains on his best behavior. You may actually find that nursing becomes the most calm, peaceful time of the day.” Rotate the “special” toys when their effectiveness wanes, or even change the distraction activity. Dalton has also found relief by having Jonah put on his own little show-and-tell presentation: “He'll hold up his Pixar trading cards and explain what each one is. I can follow along and talk about them with him, so he still gets some of my attention while Hannah nurses,” she explains. Just be sure to still try to make eye contact with your baby from time to time, since nursing is such an important part of bonding (and you've got the next 18 years to split your attention in half!).

3 Ways to Stop a Fight in Its Tracks:

Take away the toy, or whatever object of desire your kids are tussling over.

Make like Judge Judy and immediately rule in someone's favor, no waffling (just be sure to let the other kid win next time).

Dazzle 'em with distractions: “Let's get out the costumes! Give me your best tiger roar!”

To Prevent All Problems, Now and Forever: As if! You didn't think we actually have all the answers, did you? Hopefully, though, these broad strokes will help you solve some of the most common sibling issues you come across. And since you're so smart (and good-looking—don't think we didn't notice!), you'll figure out the others by trial and error. In doing so, you'll be helping all those squabbling brothers and sisters grow up into the best people they can be: friends.